The present invention relates to a beer pouring method and apparatus, and more particularly to a beer pouring method and apparatus for pouring beer by movements similar to a person pouring beer into a vessel such as a glass in order to determine the period of the beer foam stability and a system for measuring and evaluating the period of the foam stability.
The inventors have developed an apparatus for pouring beer into a vessel which approximates the movements of a person pouring beer based on the concept that it is important to use the foam formed when beer is poured in a manner similar to a person manually pouring beer. An example of a head maintaining test is Japanese Patent Laid-Open No. 67342/1996.
In the apparatus, a beer bottle is secured and is pivoted about the mouth thereof at a fixed speed to a predetermined angle until the bottom of the bottle comes to a predetermined height (the distance to the bottom of the glass into which beer is poured from the mouth of the beer bottle). Thereafter, a predetermined amount of beer is poured into the glass and the period of the beer foam stability is evaluated from the time when the layer of foam is formed (the time until the foam disappears: hereinafter referred to as xe2x80x9cperiod of foam stabilityxe2x80x9d). In this method, a fixed amount of beer is poured. However, the fixed amount itself is not an essential requirement.
What is required is to make the foaming conditions equal. One factor relating to foaming when beer is poured into a glass is the pouring force and the time required for pouring when the same glass is used. For the evaluation of the foam stability property, it is necessary to control this factor to the same conditions. Controlling this factor to the same conditions means pouring a predetermined amount of beer in an equal amount of time. Accordingly, the object of evaluation of the foam stability is achieved by controlling the pouring time and the pouring amount to be equal.
The pouring amount is also related to the size of the pouring vessel and is set to an amount which does not cause the beer to overflow from the vessel including the foam and is not too small but the amount which makes the foaming conditions to be equal.
However, with the method described above, especially for bottles, bottles do not have the same shape, and an equal amount of beer may not be poured when bottles are tilted at the same angle. In other words, the foaming conditions may not be equal between beer bottles.
Further, in the pouring method described above, even though beer is poured under the same conditions for foam forming and foam stability, the shape and temperature of the pouring vessel, the state of the inner surface of the vessel and the pouring height (the amount of foam formed differs according to the force of impact of the beer striking the vessel, the amount of foam increasing as the force of impact increases), may be different and the layer of foam is frequently different.
According to the results of the research conducted by the inventors, foaming is different between different kinds of beer (good or bad foaming qualities), and a thicker layer of foam is formed by beer having better foaming qualities if the other conditions are identical. Further, since foaming and foam stability are different properties, it is not reasonable to determine the foam stability property from the period of the foam stability alone (the time until the ratio of the foam to the total amount of beer becomes smaller than a fixed value).
Accordingly, it is difficult to form a foam layer of an equal thickness on a sample, which is the essential requirement in an evaluation method.
Therefore, it is an object of the present invention to solve the above problem by making it possible to evaluate the beer foam stability property from the period of the foam stability on which a foam layer of equal thickness is formed by providing a method and apparatus for pouring beer as well as a system for measuring and evaluating the period of foam stability to realize measuring operation of the period of the foam stability.
To achieve this object, the present invention provides a method for evaluating period of beer foam stability, comprising the steps of pouring a fixed amount of prescribed beer into a standard glass from a height considered suitable for forming a layer of foam with the thickness of a predetermined standard to obtain a sample, measuring the foam thickness and period of foam stability of said sample, comparing the foam thickness value and period of foam stability value of said sample with said predetermined standard, for adjusting the pouring height to a height suitable for forming a foam thickness which approximates more closely the foam thickness of said preset standard and repeating the pouring of a fixed amount of prescribed beer into a standard glass to obtain a new sample, and for measuring and storing the foam thickness and period of foam stability of the newly obtained sample, repeating the above steps for a plurality of samples, reading the period of foam stability which corresponds to said preset standard from a graph obtained by plotting the foam layer thickness values of said plurality of samples versus the period of foam stability values.
The present invention further provides a method and an apparatus for tilting a beer bottle to pour beer into a glass, characterized in that the mouth of a bottle is positioned at a height for forming a foam layer of a thickness which approximates a preset standard, and a fixed amount of beer is poured into a glass placed below the mouth of the bottle by tilting the bottle.
The present invention offers an advantage is that the use of a novel beer pouring apparatus which can pour a fixed amount of beer makes it possible to evaluate the period of beer foam stability precisely from the thickness of the layer of foam formed on the beer.